Sound-iwoduction in the Lamellicorn Beetles. 74-7 



number of antecnal joints occurring in neai'ly all Lamelli- 

 corn families, as affording the criterion of a really equiva- 

 lent group. In the extended sense here proposed the 

 Geotrupidag are characterized by a small clypeus whicii 

 leaves entirely exposed the extruded labrum, large more 

 or less crescent-shaped mandibles, six movable ventral 

 segments and all the pairs of coxae in close proximity. It 

 may be expected that all the larvae will be found to have 

 the legs adapted for the purpose of stridulation as in those 

 of the genus Geotrupes, the only one as yet examined. 

 The sub-families may be classified as follows : — 



a Antenna? 11-jointed Geotrupinae. 



{a) „ 10- „ 



b Mouth parts well developed : mandibles and 

 maxillfe toothed, 

 c Stridulation ventral : tibial spines simple. 



d Stridulating plate on hind coxse . . Orphninse. 

 (d) „ ,, in hind coxal cavity Taurocerastinse. 



(c) Stridulation doi-sal : a pectinate spine to 



middle tibia Ochodaeinse. 



(b) Mouth parts degenerate: mandibles and 



maxillte without teeth Idiostominae. 



The Idiostominas consist of the two species of Idiostoma 

 alone and the Ochodasinse of the siuo-le large genus 

 Ochodmus. The three species belonging to the genera 

 Tauroccrastcs and Fricldus form the Taurocerastinse, and 

 the Orphninse include Hyhalus, Orphmts, yEgidium, JEgi- 

 dinus, Sissantohius {Dreimnognatlmts), and a few other 

 genera unkoown to me. 



According to recent views upon the classification of the 

 Coleoptera the primary divisions of the Lamellicoruia 

 are the Passalidse, Lucanidse and Scarabaeidas, the last 

 corresponding to the whole of the Lamellicornia of 

 Lacordaire, who separated the first two divisions under 

 the name of Pectinicornia. In Gemminger and Harold's 

 Catalogue the Passalidse are actually merged in the 

 Lucanidse. The relationship between these two families 

 is not really very close, however, whereas there is a 

 relationship between the Passalid^e and the forms I have 

 comprised in the family Geotrupidae which has not hitherto 

 been remarked. The two types are certainly distinguished 

 by a wide difference in outward form, the Passalidas, in 

 correspondence with their highly peculiar manner of life, 



